1 #ifndef SCSI_TRANSPORT_SRP_H
2 #define SCSI_TRANSPORT_SRP_H
3 
4 #include <linux/transport_class.h>
5 #include <linux/types.h>
6 #include <linux/mutex.h>
7 
8 #define SRP_RPORT_ROLE_INITIATOR 0
9 #define SRP_RPORT_ROLE_TARGET 1
10 
11 struct srp_rport_identifiers {
12 	u8 port_id[16];
13 	u8 roles;
14 };
15 
16 /**
17  * enum srp_rport_state - SRP transport layer state
18  * @SRP_RPORT_RUNNING:   Transport layer operational.
19  * @SRP_RPORT_BLOCKED:   Transport layer not operational; fast I/O fail timer
20  *                       is running and I/O has been blocked.
21  * @SRP_RPORT_FAIL_FAST: Fast I/O fail timer has expired; fail I/O fast.
22  * @SRP_RPORT_LOST:      Port is being removed.
23  */
24 enum srp_rport_state {
25 	SRP_RPORT_RUNNING,
26 	SRP_RPORT_BLOCKED,
27 	SRP_RPORT_FAIL_FAST,
28 	SRP_RPORT_LOST,
29 };
30 
31 /**
32  * struct srp_rport - SRP initiator or target port
33  *
34  * Fields that are relevant for SRP initiator and SRP target drivers:
35  * @dev:               Device associated with this rport.
36  * @port_id:           16-byte port identifier.
37  * @roles:             Role of this port - initiator or target.
38  *
39  * Fields that are only relevant for SRP initiator drivers:
40  * @lld_data:          LLD private data.
41  * @mutex:             Protects against concurrent rport reconnect /
42  *                     fast_io_fail / dev_loss_tmo activity.
43  * @state:             rport state.
44  * @reconnect_delay:   Reconnect delay in seconds.
45  * @failed_reconnects: Number of failed reconnect attempts.
46  * @reconnect_work:    Work structure used for scheduling reconnect attempts.
47  * @fast_io_fail_tmo:  Fast I/O fail timeout in seconds.
48  * @dev_loss_tmo:      Device loss timeout in seconds.
49  * @fast_io_fail_work: Work structure used for scheduling fast I/O fail work.
50  * @dev_loss_work:     Work structure used for scheduling device loss work.
51  */
52 struct srp_rport {
53 	/* for initiator and target drivers */
54 
55 	struct device dev;
56 
57 	u8 port_id[16];
58 	u8 roles;
59 
60 	/* for initiator drivers */
61 
62 	void			*lld_data;
63 
64 	struct mutex		mutex;
65 	enum srp_rport_state	state;
66 	int			reconnect_delay;
67 	int			failed_reconnects;
68 	struct delayed_work	reconnect_work;
69 	int			fast_io_fail_tmo;
70 	int			dev_loss_tmo;
71 	struct delayed_work	fast_io_fail_work;
72 	struct delayed_work	dev_loss_work;
73 };
74 
75 /**
76  * struct srp_function_template
77  *
78  * Fields that are only relevant for SRP initiator drivers:
79  * @has_rport_state: Whether or not to create the state, fast_io_fail_tmo and
80  *     dev_loss_tmo sysfs attribute for an rport.
81  * @reset_timer_if_blocked: Whether or srp_timed_out() should reset the command
82  *     timer if the device on which it has been queued is blocked.
83  * @reconnect_delay: If not NULL, points to the default reconnect_delay value.
84  * @fast_io_fail_tmo: If not NULL, points to the default fast_io_fail_tmo value.
85  * @dev_loss_tmo: If not NULL, points to the default dev_loss_tmo value.
86  * @reconnect: Callback function for reconnecting to the target. See also
87  *     srp_reconnect_rport().
88  * @terminate_rport_io: Callback function for terminating all outstanding I/O
89  *     requests for an rport.
90  * @rport_delete: Callback function that deletes an rport.
91  *
92  * Fields that are only relevant for SRP target drivers:
93  * @tsk_mgmt_response: Callback function for sending a task management response.
94  * @it_nexus_response: Callback function for processing an IT nexus response.
95  */
96 struct srp_function_template {
97 	/* for initiator drivers */
98 	bool has_rport_state;
99 	bool reset_timer_if_blocked;
100 	int *reconnect_delay;
101 	int *fast_io_fail_tmo;
102 	int *dev_loss_tmo;
103 	int (*reconnect)(struct srp_rport *rport);
104 	void (*terminate_rport_io)(struct srp_rport *rport);
105 	void (*rport_delete)(struct srp_rport *rport);
106 	/* for target drivers */
107 	int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int);
108 	int (* it_nexus_response)(struct Scsi_Host *, u64, int);
109 };
110 
111 extern struct scsi_transport_template *
112 srp_attach_transport(struct srp_function_template *);
113 extern void srp_release_transport(struct scsi_transport_template *);
114 
115 extern void srp_rport_get(struct srp_rport *rport);
116 extern void srp_rport_put(struct srp_rport *rport);
117 extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
118 				       struct srp_rport_identifiers *);
119 extern void srp_rport_del(struct srp_rport *);
120 extern int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo,
121 			 int dev_loss_tmo);
122 extern int srp_reconnect_rport(struct srp_rport *rport);
123 extern void srp_start_tl_fail_timers(struct srp_rport *rport);
124 extern void srp_remove_host(struct Scsi_Host *);
125 extern void srp_stop_rport_timers(struct srp_rport *rport);
126 
127 /**
128  * srp_chkready() - evaluate the transport layer state before I/O
129  * @rport: SRP target port pointer.
130  *
131  * Returns a SCSI result code that can be returned by the LLD queuecommand()
132  * implementation. The role of this function is similar to that of
133  * fc_remote_port_chkready().
134  */
135 static inline int srp_chkready(struct srp_rport *rport)
136 {
137 	switch (rport->state) {
138 	case SRP_RPORT_RUNNING:
139 	case SRP_RPORT_BLOCKED:
140 	default:
141 		return 0;
142 	case SRP_RPORT_FAIL_FAST:
143 		return DID_TRANSPORT_FAILFAST << 16;
144 	case SRP_RPORT_LOST:
145 		return DID_NO_CONNECT << 16;
146 	}
147 }
148 
149 #endif
150